Mutual Conversion of Strings and Numbers in C Language

1. String to number

If it is a single character, you can use character-'0' to convert it to a number

char  a = '8';
int b = a-'0';

If it is a string, it is recommended to use the atoi function

char time[10] = "1234";
atoi(time);

2. Convert numbers to strings

char result[10]={0};
//把10进制的20转换成字符串存储早result里
itoa(20,result,10);

char time[10] = {0};
sprintf(time, "%d", 31);

 If it is a single character, you can use character + '0' to convert it to a number

int b = 9;
char  a = b+'0';