Este tópico discutirá várias maneiras de reverter uma string na linguagem de programação C. Invertendo uma string é a técnica que inverte ou altera a ordem de uma determinada string para que o último caractere da string se torne o primeiro caractere da string e assim por diante. Além disso, também podemos verificar o Palíndromo de uma determinada string invertendo a string original.
Por exemplo, inserimos uma string ' MAÇÃ ', e então use o algoritmo reverso. O algoritmo reverso retorna a string ' ELPPA 'que é completamente inverso da string original.
Diferentes maneiras de encontrar o reverso de uma string em C
A seguir estão as várias maneiras de encontrar o reverso de uma string na linguagem de programação C:
- Reverta uma string usando a função strrev()
- Reverter uma string sem usar a função de biblioteca
- Reverter uma string usando a função de recursão
- Reverter uma string usando loop for
- Reverter uma string usando loop while
- Reverter uma string usando ponteiros
- Inverta uma string para verificar o Palíndromo
Programa 1: Imprima o reverso de uma string usando a função strrev()
Vamos considerar um exemplo para imprimir o reverso de uma string usando a função strrev().
Programa1.c
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#include #include int main() { char str[40]; // declare the size of character string printf ('
Enter a string to be reversed: '); scanf ('%s', str); // use strrev() function to reverse a string printf ('
After the reverse of a string: %s ', strrev(str)); return 0; } Saída
Enter a string to be reversed: AMBULANCE After the reverse of a string: ECNALUBMA
Programa 2: Imprimir o reverso de uma string sem usar a função de biblioteca
Vamos considerar um exemplo para imprimir o reverso de uma string usando uma função definida pelo usuário.
Programa2.c
#include #include // function definition of the revstr() void revstr(char *str1) { // declare variable int i, len, temp; len = strlen(str1); // use strlen() to get the length of str string // use for loop to iterate the string for (i = 0; i <len 2; i++) { temp variable use to temporary hold the string str1[i]="str1[len" - i 1]; str1[len 1]="temp;" } int main() char str[50]; size of printf (' enter string: '); gets(str); gets() function take
before reversing %s
', str); call revstr() revstr(str); after %s', < pre> <p> <strong>Output</strong> </p> <pre> Enter the string: Welcome Friends Before reversing the string: Welcome Friends After reversing the string: sdneirF emocleW </pre> <h3>Program 3: Print the reverse of a string using the recursion function</h3> <p>Let's consider an example to print the reverse of a string using the recursion function.</p> <p> <strong>Recursion function:</strong> A recursion function is a function that continuously calls the same function without using a looping statement.</p> <p> <strong>Program3.c</strong> </p> <pre> #include #include // use recursion function void revstr(char *str1) { // declare static variable static int i, len, temp; len = strlen(str1); // use strlen() to get the length of str string if (i <len 2){ temp variable use to temporary hold the string str1[i]="str1[len" - i 1]; str1[len 1]="temp;" i++; revstr(str1); recusively calls revstr() function } int main() { char str1[50]; size of printf (' enter string: '); gets(str1); gets() take
before reversing %s
', str1); call after %s', < pre> <p> <strong>Output</strong> </p> <pre> Enter the string: LIFE INSURANCE Before reversing the string: LIFE INSURANCE After reversing the string: ECNARUSNI EFIL </pre> <h3>Program 4: Print the reverse of a string using for loop</h3> <p>Let's consider an example to print the reverse of a string using for loop in C programming language.</p> <p> <strong>Program4.c</strong> </p> <pre> #include #include #include void main() { char str[50], temp; // define the size of str[] array int i, left, right, len; printf ('
Display a reverse string in the C:
'); printf (' ----------------------- '); printf ('
Enter a string to reverse order: '); scanf( '%s', &str); len = strlen(str); // get the length of the string left = 0; // set left index at 0 right = len - 1; // set right index len - 1 // use for loop to store the reverse string for (i = left; i <right; i++) { temp="str[i];" str[i]="str[right];" str[right]="temp;" right--; } printf (' the reverse of original string is: %s ', str); getch(); < pre> <p> <strong>Output</strong> </p> <pre> Display a reverse string in the C: ----------------------- Enter a string to reverse order: APPLE The reverse of the original string is: ELPPA </pre> <h3>Program 5: Print the reverse of a string using while loop</h3> <p>Let's consider an example to print the reverse of a string using while loop in C programming language.</p> <p> <strong>Program5.c</strong> </p> <pre> #include #include int main() { char str1[50], temp; // declare and initialize the size of string array. int i = 0, j =0; printf (' Enter a string to be reversed: '); scanf( '%s', str1); j = strlen (str1) - 1; // get the length of the string // use while loop to define the condition while ( i <j) 1 { use temp variable to store the characters of str1 str1[j]="str1[i];" str1[i]="temp;" i++; i incremented by j--; j is decremented } printf (' reversed string: %s', str1); return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a string to be reversed: JAVATPOINT The reversed of the string: TNIOPTAVAJ </pre> <h3>Program 6: Print the reverse of a string using pointers</h3> <p>Let's consider an example to print the reverse of a string using pointers in the C programming language.</p> <p> <strong>Program6.c</strong> </p> <pre> #include #include int str_len( char *st); void revstr( char *st); int main() { char st[50]; printf (' Enter a string to be reversed: '); scanf( '%s', st); revstr(st); printf (' The reverse string is: %s', st); return 0; } void revstr (char *st) { int len, i; char *start, *end, temp; len = str_len (st); start = st; end = st; for (i = 0; i <len - 1; i++) end++; for (i="0;" i < len 2; { temp="*end;" *end="*start;" *start="temp;" start++; end--; } int str_len (char *ptr) while ( *(ptr + i) !=" " ) i++; return i; pre> <p> <strong>Output</strong> </p> <pre> Enter a string to be reversed: JAVATPOINT The reverse string is: TNIOPTAVAJ </pre> <h3>Program 7: Program to check whether the reverse string is a Palindrome</h3> <p>Consider a program to check whether the given string is a palindrome or not in the C programming language.</p> <p> <strong>Program7.c</strong> </p> <pre> #include #include int main () { // declare variables char str1[30]; int i, len, flag = 0; printf (' Enter a string: '); scanf ('%s', str1); len = strlen( str1 ); // get the string length for ( i = 0; i <len; i++) { str1[i] is not equal to str1[len-i-1] if (str1[i] !="str1[len" - i 1]) flag="1;" break; exit from statement } (flag) printf (' %s a palindrome string', str1); else palindrome', return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a string: madam madam is a palindrome string. </pre> <hr></len;></pre></len></pre></j)></pre></right;></pre></len></pre></len> Programa 3: Imprima o reverso de uma string usando a função de recursão
Vamos considerar um exemplo para imprimir o reverso de uma string usando a função de recursão.
Função de recursão: Uma função de recursão é uma função que chama continuamente a mesma função sem usar uma instrução de loop.
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Programa3.c
#include #include // use recursion function void revstr(char *str1) { // declare static variable static int i, len, temp; len = strlen(str1); // use strlen() to get the length of str string if (i <len 2){ temp variable use to temporary hold the string str1[i]="str1[len" - i 1]; str1[len 1]="temp;" i++; revstr(str1); recusively calls revstr() function } int main() { char str1[50]; size of printf (\' enter string: \'); gets(str1); gets() take
before reversing %s
\', str1); call after %s\', < pre> <p> <strong>Output</strong> </p> <pre> Enter the string: LIFE INSURANCE Before reversing the string: LIFE INSURANCE After reversing the string: ECNARUSNI EFIL </pre> <h3>Program 4: Print the reverse of a string using for loop</h3> <p>Let's consider an example to print the reverse of a string using for loop in C programming language.</p> <p> <strong>Program4.c</strong> </p> <pre> #include #include #include void main() { char str[50], temp; // define the size of str[] array int i, left, right, len; printf ('
Display a reverse string in the C:
'); printf (' ----------------------- '); printf ('
Enter a string to reverse order: '); scanf( '%s', &str); len = strlen(str); // get the length of the string left = 0; // set left index at 0 right = len - 1; // set right index len - 1 // use for loop to store the reverse string for (i = left; i <right; i++) { temp="str[i];" str[i]="str[right];" str[right]="temp;" right--; } printf (\' the reverse of original string is: %s \', str); getch(); < pre> <p> <strong>Output</strong> </p> <pre> Display a reverse string in the C: ----------------------- Enter a string to reverse order: APPLE The reverse of the original string is: ELPPA </pre> <h3>Program 5: Print the reverse of a string using while loop</h3> <p>Let's consider an example to print the reverse of a string using while loop in C programming language.</p> <p> <strong>Program5.c</strong> </p> <pre> #include #include int main() { char str1[50], temp; // declare and initialize the size of string array. int i = 0, j =0; printf (' Enter a string to be reversed: '); scanf( '%s', str1); j = strlen (str1) - 1; // get the length of the string // use while loop to define the condition while ( i <j) 1 { use temp variable to store the characters of str1 str1[j]="str1[i];" str1[i]="temp;" i++; i incremented by j--; j is decremented } printf (\' reversed string: %s\', str1); return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a string to be reversed: JAVATPOINT The reversed of the string: TNIOPTAVAJ </pre> <h3>Program 6: Print the reverse of a string using pointers</h3> <p>Let's consider an example to print the reverse of a string using pointers in the C programming language.</p> <p> <strong>Program6.c</strong> </p> <pre> #include #include int str_len( char *st); void revstr( char *st); int main() { char st[50]; printf (' Enter a string to be reversed: '); scanf( '%s', st); revstr(st); printf (' The reverse string is: %s', st); return 0; } void revstr (char *st) { int len, i; char *start, *end, temp; len = str_len (st); start = st; end = st; for (i = 0; i <len - 1; i++) end++; for (i="0;" i < len 2; { temp="*end;" *end="*start;" *start="temp;" start++; end--; } int str_len (char *ptr) while ( *(ptr + i) !=" " ) i++; return i; pre> <p> <strong>Output</strong> </p> <pre> Enter a string to be reversed: JAVATPOINT The reverse string is: TNIOPTAVAJ </pre> <h3>Program 7: Program to check whether the reverse string is a Palindrome</h3> <p>Consider a program to check whether the given string is a palindrome or not in the C programming language.</p> <p> <strong>Program7.c</strong> </p> <pre> #include #include int main () { // declare variables char str1[30]; int i, len, flag = 0; printf (' Enter a string: '); scanf ('%s', str1); len = strlen( str1 ); // get the string length for ( i = 0; i <len; i++) { str1[i] is not equal to str1[len-i-1] if (str1[i] !="str1[len" - i 1]) flag="1;" break; exit from statement } (flag) printf (\' %s a palindrome string\', str1); else palindrome\', return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a string: madam madam is a palindrome string. </pre> <hr></len;></pre></len></pre></j)></pre></right;></pre></len> Programa 4: Imprimir o reverso de uma string usando loop for
Vamos considerar um exemplo para imprimir o reverso de uma string usando o loop for na linguagem de programação C.
Programa4.c
#include #include #include void main() { char str[50], temp; // define the size of str[] array int i, left, right, len; printf ('
Display a reverse string in the C:
'); printf (' ----------------------- '); printf ('
Enter a string to reverse order: '); scanf( '%s', &str); len = strlen(str); // get the length of the string left = 0; // set left index at 0 right = len - 1; // set right index len - 1 // use for loop to store the reverse string for (i = left; i <right; i++) { temp="str[i];" str[i]="str[right];" str[right]="temp;" right--; } printf (\' the reverse of original string is: %s \', str); getch(); < pre> <p> <strong>Output</strong> </p> <pre> Display a reverse string in the C: ----------------------- Enter a string to reverse order: APPLE The reverse of the original string is: ELPPA </pre> <h3>Program 5: Print the reverse of a string using while loop</h3> <p>Let's consider an example to print the reverse of a string using while loop in C programming language.</p> <p> <strong>Program5.c</strong> </p> <pre> #include #include int main() { char str1[50], temp; // declare and initialize the size of string array. int i = 0, j =0; printf (' Enter a string to be reversed: '); scanf( '%s', str1); j = strlen (str1) - 1; // get the length of the string // use while loop to define the condition while ( i <j) 1 { use temp variable to store the characters of str1 str1[j]="str1[i];" str1[i]="temp;" i++; i incremented by j--; j is decremented } printf (\' reversed string: %s\', str1); return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a string to be reversed: JAVATPOINT The reversed of the string: TNIOPTAVAJ </pre> <h3>Program 6: Print the reverse of a string using pointers</h3> <p>Let's consider an example to print the reverse of a string using pointers in the C programming language.</p> <p> <strong>Program6.c</strong> </p> <pre> #include #include int str_len( char *st); void revstr( char *st); int main() { char st[50]; printf (' Enter a string to be reversed: '); scanf( '%s', st); revstr(st); printf (' The reverse string is: %s', st); return 0; } void revstr (char *st) { int len, i; char *start, *end, temp; len = str_len (st); start = st; end = st; for (i = 0; i <len - 1; i++) end++; for (i="0;" i < len 2; { temp="*end;" *end="*start;" *start="temp;" start++; end--; } int str_len (char *ptr) while ( *(ptr + i) !=" " ) i++; return i; pre> <p> <strong>Output</strong> </p> <pre> Enter a string to be reversed: JAVATPOINT The reverse string is: TNIOPTAVAJ </pre> <h3>Program 7: Program to check whether the reverse string is a Palindrome</h3> <p>Consider a program to check whether the given string is a palindrome or not in the C programming language.</p> <p> <strong>Program7.c</strong> </p> <pre> #include #include int main () { // declare variables char str1[30]; int i, len, flag = 0; printf (' Enter a string: '); scanf ('%s', str1); len = strlen( str1 ); // get the string length for ( i = 0; i <len; i++) { str1[i] is not equal to str1[len-i-1] if (str1[i] !="str1[len" - i 1]) flag="1;" break; exit from statement } (flag) printf (\' %s a palindrome string\', str1); else palindrome\', return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a string: madam madam is a palindrome string. </pre> <hr></len;></pre></len></pre></j)></pre></right;> Programa 5: Imprima o reverso de uma string usando o loop while
Vamos considerar um exemplo para imprimir o reverso de uma string usando o loop while na linguagem de programação C.
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Programa5.c
#include #include int main() { char str1[50], temp; // declare and initialize the size of string array. int i = 0, j =0; printf (' Enter a string to be reversed: '); scanf( '%s', str1); j = strlen (str1) - 1; // get the length of the string // use while loop to define the condition while ( i <j) 1 { use temp variable to store the characters of str1 str1[j]="str1[i];" str1[i]="temp;" i++; i incremented by j--; j is decremented } printf (\' reversed string: %s\', str1); return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a string to be reversed: JAVATPOINT The reversed of the string: TNIOPTAVAJ </pre> <h3>Program 6: Print the reverse of a string using pointers</h3> <p>Let's consider an example to print the reverse of a string using pointers in the C programming language.</p> <p> <strong>Program6.c</strong> </p> <pre> #include #include int str_len( char *st); void revstr( char *st); int main() { char st[50]; printf (' Enter a string to be reversed: '); scanf( '%s', st); revstr(st); printf (' The reverse string is: %s', st); return 0; } void revstr (char *st) { int len, i; char *start, *end, temp; len = str_len (st); start = st; end = st; for (i = 0; i <len - 1; i++) end++; for (i="0;" i < len 2; { temp="*end;" *end="*start;" *start="temp;" start++; end--; } int str_len (char *ptr) while ( *(ptr + i) !=" " ) i++; return i; pre> <p> <strong>Output</strong> </p> <pre> Enter a string to be reversed: JAVATPOINT The reverse string is: TNIOPTAVAJ </pre> <h3>Program 7: Program to check whether the reverse string is a Palindrome</h3> <p>Consider a program to check whether the given string is a palindrome or not in the C programming language.</p> <p> <strong>Program7.c</strong> </p> <pre> #include #include int main () { // declare variables char str1[30]; int i, len, flag = 0; printf (' Enter a string: '); scanf ('%s', str1); len = strlen( str1 ); // get the string length for ( i = 0; i <len; i++) { str1[i] is not equal to str1[len-i-1] if (str1[i] !="str1[len" - i 1]) flag="1;" break; exit from statement } (flag) printf (\' %s a palindrome string\', str1); else palindrome\', return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a string: madam madam is a palindrome string. </pre> <hr></len;></pre></len></pre></j)> Programa 6: Imprima o reverso de uma string usando ponteiros
Vamos considerar um exemplo para imprimir o reverso de uma string usando ponteiros na linguagem de programação C.
Programa6.c
#include #include int str_len( char *st); void revstr( char *st); int main() { char st[50]; printf (' Enter a string to be reversed: '); scanf( '%s', st); revstr(st); printf (' The reverse string is: %s', st); return 0; } void revstr (char *st) { int len, i; char *start, *end, temp; len = str_len (st); start = st; end = st; for (i = 0; i <len - 1; i++) end++; for (i="0;" i < len 2; { temp="*end;" *end="*start;" *start="temp;" start++; end--; } int str_len (char *ptr) while ( *(ptr + i) !=" " ) i++; return i; pre> <p> <strong>Output</strong> </p> <pre> Enter a string to be reversed: JAVATPOINT The reverse string is: TNIOPTAVAJ </pre> <h3>Program 7: Program to check whether the reverse string is a Palindrome</h3> <p>Consider a program to check whether the given string is a palindrome or not in the C programming language.</p> <p> <strong>Program7.c</strong> </p> <pre> #include #include int main () { // declare variables char str1[30]; int i, len, flag = 0; printf (' Enter a string: '); scanf ('%s', str1); len = strlen( str1 ); // get the string length for ( i = 0; i <len; i++) { str1[i] is not equal to str1[len-i-1] if (str1[i] !="str1[len" - i 1]) flag="1;" break; exit from statement } (flag) printf (\' %s a palindrome string\', str1); else palindrome\', return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a string: madam madam is a palindrome string. </pre> <hr></len;></pre></len> Programa 7: Programa para verificar se a string reversa é um Palíndromo
Considere um programa para verificar se uma determinada string é um palíndromo ou não na linguagem de programação C.
Programa7.c
#include #include int main () { // declare variables char str1[30]; int i, len, flag = 0; printf (' Enter a string: '); scanf ('%s', str1); len = strlen( str1 ); // get the string length for ( i = 0; i <len; i++) { str1[i] is not equal to str1[len-i-1] if (str1[i] !="str1[len" - i 1]) flag="1;" break; exit from statement } (flag) printf (\\' %s a palindrome string\\', str1); else palindrome\\', return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a string: madam madam is a palindrome string. </pre> <hr></len;>