별찍기

1) 

for ( let i=0; i<5; i++ ) {
    let str = "";

    for ( let j=0; j<i+1; j++ ) {
        str += "*";
    }

    console.log(str);
}

 

2)

for ( let i=0; i<5; i++ ) {
    let str = "";

    for ( let j=0; j<5-i; j++ ) {
        str += "*";
    }

    console.log(str);
}

 

3)

for ( let i=0; i<5; i++ ) {
    let str="";
    
    for ( let j=0; j<5-i-1; j++ ) {
        str += " ";
    }
    for ( let k=0; k<i+1; k++) {
        str += "*";
    }

    console.log(str);
}

 

4)

for ( let i=0; i<5; i++ ) {
    let str="";

    for ( let k=0; k<i; k++ ) {
        str += " ";
    }

    for ( let j=0; j<5-i; j++ ) {
        str += "*";
    }

    console.log(str);
}

 

5)

for ( let i=0; i<5; i++ ) {
    let str="";
    for ( let j=0; j<5-i-1; j++ ) {
        str += " ";
    }
    for ( let k=0; k<2*i+1; k++ ) {
        str += "*";
    }
    console.log(str);
}

 

6)

for ( let i=0; i<5; i++) {
    let str="";
    for ( let j=0; j<i; j++ ) {
        str += " ";
    }
    for ( let j=0; j<-2*i+9; j++ ) {
        str += "*"
    }
    console.log(str);
}