control structure - if else

if-and-else.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.9.0;

contract demo_if {
    uint x = 10;
    function Compare (uint _x) external view returns (string memory){
        if (_x >= x) {   // if section
            return 'Given value is greater or equal to x';}
        else {          // else section
            return 'Given value is less than x';
        }
    }
}    
    

if-else_if-else-structure.sol

if (condition) {
  body ;}
else if (another condition) {
  body ; }
else {
  body ; }

if-else_if-else_all.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.9.0;

contract demo_if {

    uint x;

    function CompNum (uint _x) public view returns (string memory) {
        if (_x > x) {
            return 'The number entered is bigger';
        } else if (_x < x) {
            return 'Number entered is lesser';
        } else {
            return 'Both numbers are equal';
        }
        
    }
}

multiple-else-if.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.9.0;

contract demo_if2 {

    function CompNum (uint _x) public pure returns (string memory) {
        if (_x == 1) {
            return 'Monday'; }
        else if (_x == 2) {
            return 'Tuesday';}
        else if (_x == 3) {
            return 'WednesDay';}
        else if (_x == 4) {
            return 'Thursay';}
        else if (_x == 5) {
            return 'Friday';}
        else if ((_x == 6) || (_x == 7)) {
            return 'It is a Weekend';}
        else {
            return 'Invalid Input';
        }
    }
}

only-if.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.9.0;

contract demo_if {
    uint x = 10;
    function Compare (uint _x) external view returns (bool){
        if (_x >= x) {    // only one if statement
            return true;
        }
    }
}    
    

ternary-if-else.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.9.0;

contract demo_if {
    uint x = 10;
    function Compare (uint _x) external view returns (string memory){
        return _x >= x ? 'Given value is greater or equal to x' : 'Given value is less than x' ;
        
    }
}