Convert string to integer

Here we explain C program to convert string to an integer. String should consist of digits only and an optional ‘-‘ (minus) sign at the beginning for integers. For string containing other characters, we can stop conversion as soon as a non-digit character is encountered. But in our program, we will handle the ideal case when only valid characters are present in the string.

  #include<stdio.h>
    int stringToInt(char[] );
    int main(){
        char str[10];
        int intValue;
printf("\n\t\t\t...Welcome To EduNews.Tech... ");

        printf("\n\nEnter any integer as a string: ");
        scanf("%s",str);
       intValue = stringToInt(str); //converting string value to integer type by making its function.
        printf("Equivalent integer value: %d",intValue);
printf("\n\n\n\t\t\tThankyou for Joining Us !");
    printf("\n\t\t\t\t!Regards EduNews !");

        return 0;
    }
    int stringToInt(char str[])       //it is a function made to convert the string value to integer value.
       {
        int i=0,sum=0;
        while(str[i]!='\0')                     //string not equals to null
         {
             if(str[i]< 48 || str[i] > 57)      // ascii value of numbers are between 48 and 57.
                {
                 printf("Unable to convert it into integer.\n");
                 return 0;
             }
             else
            {
                 sum = sum*10 + (str[i] - 48);
                 i++;
             }
        }
        return sum;
    }

Program Output:

I hope this post helps you to understand  the conversion of string to int without using library functions and its implementation in C programming language.

Keep coding 🙂