C language design realizes mutual conversion between hexadecimal and decimal numbers

1. Convert hexadecimal numbers to decimal numbers

1. Design a C language code to convert hexadecimal numbers such as 0xFEFF to decimal

The following is an example of C language code to convert a hexadecimal number to decimal:

#include <stdio.h>
#include <stdlib.h>

int main() {
    char hexNum[10];  // 存储输入的十六进制数
    int decNum;       // 存储转换后的十进制数

    printf("请输入一个十六进制数：");
    scanf("%s", hexNum);//例如0xFEFF或0x00800000

    // 使用 strtol 函数将十六进制数转换为十进制数
    decNum = strtol(hexNum, NULL, 16);

    printf("转换后的十进制数为：%d\n", decNum);

    return 0;
}

In the above code, we used strtolthe function to convert from hexadecimal to decimal. strtolThe first parameter of the function is the string to be converted, the second parameter is a pointer to a character pointer to store the remainder without conversion (if any), and the third parameter specifies the base of the conversion , where 16 is used for hexadecimal.

You can enter a hexadecimal number such as "0xFEFF" when the program is running, and it will output the converted decimal number 65279.

请输入一个十六进制数：0xFEFF
转换后的十进制数为：65279
请输入一个十六进制数：0x00800000
转换后的十进制数为：8388608

 2. Convert decimal numbers to hexadecimal numbers

1. Design a C language code to convert decimal to hexadecimal number and the form of hexadecimal number is 0x0000000, this form:

The following is a C language code example for converting a decimal number to a hexadecimal number of the form 0x0000000:

#include <stdio.h>
#include <stdlib.h>

void printHex(int decimalValue) {
    printf("Hex: 0x%X\n", decimalValue);
}

int main() {
    char tmp_decimalValue[10]; // 十进制数
    printf("请输入一个十进制数：");
    scanf("%s", tmp_decimalValue);//例如65279
    int decimalValue = atoi(tmp_decimalValue);
    printHex(decimalValue);

    return 0;
}

In the above code, we define a function printHex()to print the hexadecimal number format like 0x0000000. We use printf()the function's format string to specify the output format, which %Xmeans print a hexadecimal number.

For the decimal number 65279, the above code would output:

请输入一个十进制数：65279
Hex: 0xFEFF

3. Summary

Through the above two code examples, the study assumes different data and performs the conversion process;